Is it legal to have an additional addendum for a purchase price for a home. I currently have a loan through the banks for 178,000.00 and an additional addendum for $17,000.00 going to the oner of the home.

Yes, addendum are quite common with contracts. What you should be aware of would be to make sure the addendum is referenced in the ‘whole agreement’ so that it doesn’t become an entity in itself. All parts of a contract, including addendum, should work together ‘in concert’. Make sure you completely understand how the ‘whole agreement’ works, including any & all addendum. If you are not sure, it might be time to review it all with your agent or a Real Estate Attorney.